### Top Posts

### Recent comments

- Jon Awbrey on Mathematical diversity
- Peter Cameron on Mathematical diversity
- Peter Cameron on Finite geometry in Brighton
- jgilbey2014 on All kinds of mathematics, 1
- José Manuel Dos Santos Dos Santis on All kinds of mathematics, 1

### Blogroll

- Alexander Konovalov
- Annoying precision
- Astronomy Picture of the Day
- Azimuth
- Bad science
- Bob Walters
- British Combinatorial Committee
- CIRCA tweets digest
- CoDiMa
- Coffee, love, and matrix algebra
- Comfortably numbered
- Computational semigroup theory
- DC's Improbable Science
- Diamond Geezer
- Exploring East London
- From hill to sea
- Gödel's lost letter and P=NP
- Gil Kalai
- Haris Aziz
- Intersections
- Jane's London
- Jon Awbrey
- LMS blogs page
- Log24
- London Algebra Colloquium
- London Reconnections
- Marie Cameron's blog
- MathBlogging
- Micromath
- Neill Cameron
- neverendingbooks
- Noncommutative geometry
- numericana hall of fame
- Paul Goldberg
- Robert A. Wilson's blog
- Sheila's blog
- Since it is not …
- Spitalfields life
- St Albans midweek lunch
- Stubborn mule
- Sylvy's mathsy blog
- SymOmega
- Tangential thoughts
- Terry Tao
- The Aperiodical
- The De Morgan Journal
- The ICA
- The London column
- The Lumber Room
- The matroid union
- Theorem of the day
- Tim Gowers
- Vynmath
- XKCD

### Find me on the web

### Cameron Counts: RSS feeds

### Meta

# Tag Archives: association scheme

## Synchronization and separation in the Johnson schemes

Today a paper by Mohammed Aljohani, John Bamberg and me went on the arXiv on this topic. Here is a brief summary of what it is about. Synchronization comes in several flavours, and the point of the paper is to … Continue reading

Posted in exposition, Uncategorized
Tagged association scheme, Peter Keevash, Philippe Delsarte, separation, synchronization
Leave a comment

## More graphs

John Bamberg is reporting on New Directions in Combinatorics on SymOmega (his report on Day 1 is here), so I will not even attempt to be comprehensive, but will just pick some plums. Not very long ago, I reported the … Continue reading

Posted in events, exposition, history
Tagged association scheme, characters, Graham Higman, Moore graph, partial difference set, Stefaan De Winter
Leave a comment

## Terminology: association scheme or coherent configuration?

At the Villanova conference, many of the talks were about association schemes or coherent configurations, or indeed generalisations of these. A certain tension between different uses of these terms was evident. I’d like to set down my own views here. … Continue reading

Posted in exposition, history
Tagged association scheme, Bose, coherent configuration, Higman, Leman, Mesner, Nair, Schur ring, Shimamoto, Terwilliger, Weisfeiler
2 Comments

## Multiply transitive permutation sets

Bill Fahle asked, in a comment on the preceding post, for information about sets of permutations which are multiply transitive (but not necessarily groups or sharply multiply transitive). I take “t-transitive set” to mean a set S of permutations of … Continue reading

## Coherent configurations and all that, 1

I’m off to Lisbon next week for three weeks. Among other things, I will be giving four lectures at the Centre for Algebra at the University of Lisbon. One of these will touch on aspects of association schemes and coherent … Continue reading